OVERCOMING ELEMENTAL IMBALANCE WITH FOOD THROUGH SHIFTS IN FEEDING BEHAVIOR: A STUDY OF THE CADDISFLY PTILOSTOMIS OCELLIFERA (TRICHOPTERA: PHRYGANEIDAE)

Caddisflies are often a major component of invertebrate communities in aquatic wetland habitats that contribute to the transfer of energy and nutrients through trophic levels. In this study we examined Ptilostomis ocellifera (Trichoptera: Phryganeidae), a mobile variety of tube-dwelling Trichoptera...

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Bibliographic Details
Published in:Journal of the Pennsylvania Academy of Science 2010-04, Vol.84 (1), p.3-10
Main Authors: WOZNIAK, JEFFREY R., MASON, BENJAMIN M.
Format: Article
Language:English
Subjects:
Animal cannibalism
BIOLOGY
Caddisflies
Diet
Ecological life histories
Food
Instars
Larvae
Nutrients
Wetland ecology
Wetlands
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Summary:Caddisflies are often a major component of invertebrate communities in aquatic wetland habitats that contribute to the transfer of energy and nutrients through trophic levels. In this study we examined Ptilostomis ocellifera (Trichoptera: Phryganeidae), a mobile variety of tube-dwelling Trichoptera which is one of the most abundant and conspicuous species of caddisfly in northwestern Pennsylvania. To gain a better understanding of caddisfly feeding behavior and food sources, we determined the nutrient composition (carbon, nitrogen, and phosphorus) of wetland detritus from permanent and semi-permanent deciduous wetlands in northwestern Pennsylvania. Furthermore, we established how caddisfly cannibalism rates varied with different nutrient quality foods and conducted a detailed analysis of caddisfly gut content across instars. We found that the C:N of semi-permanent wetland detritus (34.01 (±3.72)) was higher than permanent wetlands (18.66 (±3.22)) while the N:P of permanent wetlands (60.39 (±6.81)) was higher than semi-permanent sites (36.21 (±7.87)). The rate of caddisfly cannibalism increased from 37.5% in trials with wetland detritus as the food source to 83.3% in trials where individuals were starved for a period of three days and a nutrient poor food source (filter paper) was substituted for wetland detritus. P. ocellifera has been considered to be a detrital shredder; however, our results indicate that they function as omnivores, consuming a wide range of food sources. Gut content analysis provided dietary evidence that P. ocellifera shifted its diet from primarily wetland detritus to animal material through its development. Final instars were shown to overcome nutrient deficiency by acting as predators in the field.
ISSN:1044-6753
2475-1898